Pluto's first close-up photos have completely baffled scientists with new mysteries

The stunning new photos came from New Horizon's 15-minute flyby
on July 14, and after seeing them, scientists say they've been
left with more questions than answers.

"The terrain down toward the lower right [of Pluto's close-up
image] looks really strange. It looks like piles of grooves and
stuff, to use really technical language," said John Spencer, a
New Horizons team member, during a NASA press briefing Wednesday.
"It's baffling, and it's baffling in a very special way."

Some of these piles are actually 11,000-foot-high
mountains. "They'd stand up respectably against the Rocky
Mountains," said Spencer, who's also a planetary
scientist at the Southwest Research Institute (SwRI) in Colorado.

NASA

Here's what the mountains look like in the close-up photo, which
New Horizons took from about 478,000 miles away:

Scientists on the New Horizons team think these strange mountains
are made of something surprising: water.

"The bedrock that makes those mountains must be made of H2O," the
mission's principle investigator,
Alan Stern of SwRI, said during the press conference. "We see
water ice on Pluto for the first time. We can be very sure that
the water is there in great abundance."

There could even be geysers or cryovolcanoes in this or
other mountain ranges on Pluto:

"We haven't found geysers and we haven't found cryovolcanoes, but
this is very strong evidence that will send us looking ... for
evidence of these exact phenomena," Stern said.

The water-ice mountains and possible volcanoes are found near the
planet's "heart" — an adorably shaped geologic feature discovered
by New Horizons, which they're now calling "Tombaugh Regio"
(after Clyde Tombaugh, who discovered Pluto).

The image reveals Pluto's heart is made of a bunch of different
materials. The left lobe is a light peach color, while the right
lobe is more bluish. They don't know, for sure, what those colors
mean, but
more data in the coming months will likely crack open some of
those mysteries.

Another fascinating finding from that close-up photo?
There are almost no craters on the surface of Pluto (at
least in that area). This is incredibly surprising — planetary
scientists said today they haven't seen anything like
it.

That also means that the surface there is incredibly young
(young, at least, when it comes to planetary bodies in our solar
system). They dated that area of the planet to about 100 million
years old, compared to the 4.56-billion-year age of the Solar
System.

The springy youth of that area of Pluto could mean the dwarf
planet is still geologically active. This is another incredibly
shocking idea for researchers, since — unlike large moons the
size of Pluto — it doesn't have the tidal push-and-pull of a
giant planet to warm it up inside.

Scientists always thought a big planet's gravity was the cause of
any warmth and geological activity on such small worlds. But
nope! There's obviously something else going on on Pluto
to keep it moving and warm and making mountains.

"This may cause us to rethink what powers geological activity on
many other icy worlds," Spencer said
in a NASA press release. New Horizons think the leading
candidate for warmth is radioactive elements, like thorium

Water ice isn't the only type of ice on Pluto. This infrared
spectral image of Pluto shows methane ice abundantly coating the
dwarf planet's surface:

NASA

"We just learned that in the north polar cap, methane ice is
diluted in a thick, transparent slab of nitrogen ice resulting in
strong absorption of infrared light," New Horizons
co-investigator Will Grundy, of Lowell Observatory, said
in a press release.

But Grundy said no one is sure what the darker patches near the
equator are made of: "The spectrum appears as if the ice is less
diluted in nitrogen," he said, "or that it has a different
texture in that area."

We'll find out more about Pluto's atmosphere and chemical makeup
from light-sampling spectrometers on board the spacecraft. And as
soon as Friday, New Horizons should beam down a brand-new set of
images.